tracking pointers in hardware

[Yoav Etsion <etsman at gmail dot com>]

Hi all,

I'm designing a new hardware that needs to know which GPR contains a 
simple integer, and which contained pointer. The hardware simply needs 
different load operations for both (we're talking load/store machines, 
with no indirect addressing to make life easier).

From the compiler's perspective, all it needs is to annotate load 
operations to tell the hardware if this is a pointer or an integer (say 
LD for integers and PLD for pointers).

As far as I can see, this data is not available in the final RTL stage:
the RTL contains some pointer data about virtual registers at first, but 
it seems this data gets lost during optimizations, and mainly during the 
reload phase.

Do any of you guys have suggestions how to implement it as part of gcc?
My only idea for now is to add an RTL pass just before the final pass 
tracking dataflow to find which registers are used as addresses in 
loads/stores (but this can probably be done by dataflow tracking 
asm-to-asm filter).

Thanks,

Yoav Etsion